Field
Embodiments of the present disclosure generally relate to an apparatus for heating substrates and, more specifically, to an apparatus having an improved lamphead system with a lamp failure detector.
Description of the Related Art
Conventional lateral flow chambers may have an upper dome, a lower dome, a substrate support disposed between the upper dome and the lower dome, and a lamphead positioned under and in close proximity to the lower dome. A number of lamps are located in the lamphead and facing the back side of the substrate support. The lamps contained in the lamphead are divided into multiple, radially symmetric zones. Each zone contains multiple lamps, and the lamps are divided into pairs with each lamp pair connected to a power driver. During processing, heat radiation from the lamps radiate through the lower dome onto a rotating substrate positioned on the substrate support. In this manner, the substrate is heated to a required processing temperature.
When a lamp fails and needs to be replaced, the entire lamphead must be dropped manually in order to retrieve the faulty lamp from its receptacle from the top of the lamphead. As the lamphead is positioned in close proximity to the lower dome, disassembly of the entire lamphead to replace the faulty lamp in such a limited space requires extra effort and time, which causes longer change times and therefore slower process throughput. In addition, variation in lamp intensity due to lamp failure or poor performance can greatly compromise the desired heating temperature profile control and result in unacceptable process results. If one of the lamp filaments breaks, the conventional lamp failure detection system cannot detect which lamp in a pair has the open filament since the failure detection method measures current for two lamps connected in series. As a result, it is necessary to check both lamps for failure if a failure state is indicated for the lamp pair. Also, the lamps for a given pair are often located at some distance apart within the lamphead to minimize the impact to radiation uniformity should one of the lamps fail during substrate processing. Significant time could be saved if only the failed lamp had to be located within the lamp array, resulting in decreased down time for the lateral flow chambers.
Thus, there is a need in the art for an improved apparatus which enables fast lamp replacement, ease of service of the lamphead, and lamp failure detection.